1. Field of the Invention
This invention relates to an auto-lock slider, and more particularly to an auto-lock slide fastener slider composed of four members, i.e., a slider body, a pull tab, a locking leaf spring and a cover.
2. Description of the Related Art
FIG. 7 of the accompanying drawings shows a conventional auto-lock slide fastener slider which is disclosed in Japanese Utility Model Publication o. Sho 62-490. In this conventional auto-lock slider, the upper wing 5' of a slider body 1' has on its upper surface front and rear attachment lugs 10', 11', at a position near and forward of the rear attachment lug 11' a locking-pawl-insertion hole 141 and at a position forward of the locking-pawl-insertion hole 141 a pair of guide projections 15', the front attachment lug 10' having on its top a semi-cylindrical projection 12'. A locking leaf spring 3', which has at one end a slot 42 and at the other end a downwardly bent locking pawl 24' of which base portion is stepped so as to form a horizontal portion 41, is slidably mounted on the upper wing in such a manner that the slot 42 loosely receives the semi-cylindrical projection 12' of the front attachment lug 10 and that the horizontal portion 41 is disposed between the guide projections 15' of the upper wing 5'. An axle 19 of a pull tab 2' is inserted between the upper wing 5' and the locking leaf spring 3'. A cover 4' is attached to the attachment lugs 10', 11' over the locking leaf spring 3'.
According to the conventional auto-lock slider of FIG. 7, since the locking pawl 24', which is slidably mounted on the upper wing 5', does not come into contact with a front wall of the locking-pawl-insertion hole 141 when the locking leaf spring 3' is moved to the front side, the locking pawl 24' tends to deform so that a reliable locking operation cannot be achieved, thus causing a limited degree of durability.